Status on the Michigan‐MIT ultra‐cold polarized hydrogen jet target

Progress on the Mark‐II ultra‐cold polarized atomic hydrogen gas Jet target for the experiments NEPTUN‐A and NEPTUN at UNK is presented. We describe the performance and the present status of different components of the jet.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87525/2/698_1.pd

Shrub Invasion Decreases Diversity and Alters Community Stability in Northern Chihuahuan Desert Plant Communities

BACKGROUND:Global climate change is rapidly altering species range distributions and interactions within communities. As ranges expand, invading species change interactions in communities which may reduce stability, a mechanism known to affect biodiversity. In aridland ecosystems worldwide, the range of native shrubs is expanding as they invade and replace native grassland vegetation with significant consequences for biodiversity and ecosystem functioning. METHODOLOGY:We used two long-term data sets to determine the effects of shrub encroachment by Larrea tridentata on subdominant community composition and stability in formerly native perennial grassland dominated by Bouteloua eriopoda in New Mexico, USA. PRINCIPAL FINDINGS:Our results indicated that Larrea invasion decreased species richness during the last 100 years. We also found that over shorter temporal scales species-poor subdominant communities in areas invaded by Larrea were less stable (more variable in time) compared to species rich communities in grass-dominated vegetation. Compositional stability increased as cover of Bouteloua increased and decreased as cover of Larrea increased. SIGNIFICANCE:Changes in community stability due to altered interspecific interactions may be one mechanism by which biodiversity declines in grasslands following shrub invasion. As global warming increases, shrub encroachment into native grasslands worldwide will continue to alter species interactions and community stability both of which may lead to a decline in biodiversity

A market road to sustainable agriculture? Ecological agriculture, green food and organic agriculture in China

To the extent that free markets show little concern for the existence of externalities, they are unlikely to produce optimum outcomes with regard to the protection and enhancement of the natural environment. Accordingly, the increasing emphasis on markets to deliver development in China under Deng Xiaoping and his successors has the capacity to threaten the long-term environmental sustainability of that development. While there are good reasons to remain sceptical about the ability of market mechanisms to promote sustainable rural development in many respects, market reforms in China and the opening of the country to the outside world have nevertheless provided opportunities for farmers to engage in ecologically sensitive agriculture in the form of `green' food and organic farming. Given that these forms of agriculture reduce farmers' use of chemicals compared to conventional farming — chemicals which are costly to produce and environmentally degrading to use — they contribute to ensuring a more environmentally sustainable future for Chinese farming, post-WTO entry, whilst providing opportunities for farmers to enrich themselves at the same time: a `win–win' state of affairs. This will remain the case, however, only so long as the state is prepared to create and reinforce appropriate institutional arrangement

Assessing the Conservation Value of the Gray Ranch: Rarity, Diversity, and Representativeness

Desert Plants is published by The University of Arizona for the Boyce Thompson Southwestern Arboretum. For more information about this unique botanical journal, please email the College of Agriculture and Life Sciences Publications Office at [email protected]